1. Field of the Invention
The present invention relates to a scroll compressor which is installed in an air conditioner, a refrigerator, or the like.
2. Description of the Related Art
In conventional scroll compressors, a fixed scroll and a swiveling scroll are provided by engaging their spiral wall bodies, and fluid inside a compression chamber, formed between the wall bodies, is compressed by gradually reducing the capacity of the compression chamber as the swiveling scroll revolves around the fixed scroll.
The compression ratio in design of the scroll compressor is the ratio of the maximum capacity of the compression chamber (the capacity at the point when the compression chamber is formed by the meshing of the wall bodies) to the minimum capacity of the compression chamber (the capacity immediately before the wall bodies become unmeshed and the compression chamber disappears), and is expressed by the following equation (I).
Vi={A(xcex8suc)xc2x7L}/{A(xcex8top)xc2x7L}=A(xcex8suc)/A(xcex8top)xe2x80x83xe2x80x83(I)
In equation (I), A(xcex8) is a function expressing the cross-sectional area parallel to the rotation face of the compression chamber which alters the capacity in accordance with the rotating angle xcex8 of the swiveling scroll; xcex8suc is the rotating angle of the swiveling scroll when the compression chamber reaches its maximum capacity, xcex8top is the rotating angle of the swiveling scroll when the compression chamber reaches its minimum capacity, and L is the wrap (overlap) length of the wall bodies.
Conventionally, in order to increase the compression ratio Vi of the scroll compressor, the number of windings of the wall bodies of the both scrolls is increased to increase the cross-sectional area A(xcex8) of the compression chamber at maximum capacity. However, in the conventional method of increasing the number of windings of the wall bodies, the external shape of the scrolls is enlarged, increasing the size of the compressor; for this reason, it is difficult to use this method in an air conditioner for vehicles and the like which have strict size restrictions.
In an attempt to solve the above problems, Japanese Examined Patent Application, Second Publication, No. Sho 60-17956 (Japanese Unexamined Patent Application, First Publication, No. Sho 58-30494) proposes a scroll compressor in which the spiral top edge of each wall of a fixed scroll and a swiveling scrollwall body have a low center side and a high outer peripheral side to form a step, and the side faces of the end plates of both scrolls have high center sides and low outer peripheral sides in correspondence with the step of the top edge.
In the scroll compressor as described above, when the wrap length of the compression chamber at maximum capacity is expressed as Ll and the wrap length of the compression chamber at minimum capacity is expressed as Ls, the compression ratio Vixe2x80x2 for design purposes is expressed by the following equation (II).
Vixe2x80x2={A(xcex8suc)xc2x7Ll}/{A(xcex8top)xc2x7Ls}xe2x80x83xe2x80x83(II)
In equation (II), the wrap length Ll of the compression chamber at maximum capacity is greater than the wrap length Ls of the compression chamber at minimum capacity, so that Ll/Ls greater than 1. Therefore, the compression ratio in design can be increased without increasing the number of windings of the wall bodies.
The scroll compressor which uses scrolls having steps as described above has a problem of airtightness when a join edge, which joins the low top edge and high top edge of the wall bodies, slides against a join wall face, which joins the deep side face and the shallow side face of the end plate.
For this reason, the scrolls are processed and assembled with extremely high precision in order to preserve airtightness when sliding the join wall faces together. However, the demand for extremely high-precision processing and assembly leads to poor productivity and higher costs.
To solve the above problems, Japanese Unexamined Patent Application, First Publication, No. Hei 6-10857 discloses a constitution in which a sealing member is provided on a join edge of the wall body of one scroll, and an energizing member is used to press the sealing member against the contact wall face of the end plate of the other scroll (see FIGS. 5 and 6).
In the above method, a sealing member is provided on the join edge of the wall body of one scroll and slides against the contact wall face of the side plate of the other scroll, enabling airtightness to be preserved without requiring high-precision processing. However, there is a problem that the sealing member may fall off when a gap appears between the join edge of the wall body and the join wall face of the end plate.
In order to solve the problem, Japanese Unexamined Patent Application, First Publication, No. Hei 8-28461 discloses a scroll compressor in which the sealing member, which is provided on the join edge of the wall body, is formed in one piece with the tip seal, which seals the upper top edge of the spiral-shaped wall body, thereby preserving airtightness and preventing the sealing member from falling off when the join wall faces are separated (see FIGS. 12 and 13).
However, the above method has the following problems. Although the tip seal and the sealing member of the join wall face are provided in one piece, since the sealing member is joined to the tip seal like a cantilever, the sealing member tends to break during long time operation.
Furthermore, in the conventional scroll compressor, the tip seal is provided along the spiral-shaped top edge of the wall body, preserving airtightness between the bottom faces of the scrolls and obtaining a compression chamber with negligible leakage, increasing the compression efficiency.
In the scroll compressor using a step in the scroll as described above, the tip seal is separated by the top edge of the stepped wall body, however, in the tip seal positioned on the outer peripheral side of the scroll, sufficient pressing force cannot be achieved against the top edge of the wall bodies due to low pressure against the rear faces thereof, and the tip seal cannot function properly as a seal. When there is considerable leakage from the compression chamber, an equivalent dynamic force is needed for recompression and dynamic force loss of the driving power is incurred; this is is not efficient.
In view of the above problems, it is an object of the present invention to provide a highly reliable scroll compressor which prevents leakage of fluid to be transported by increasing the airtightness between a fixed scroll and a swiveling scroll, thereby increasing the compression ratio and increasing capability.
It is another object of the present invention, in a scroll compressor using a scroll having a step, to increase the seal function of a tip seal so as to reduce leakage from the compression chamber, and eliminate loss of power to be used as recompression power for the leakage, thereby increasing the operating efficiency of the compressor.
In order to achieve the above objects, the scroll compressor of the present invention has the following constitution.
A first aspect according to the present invention is to provide A scroll compressor comprising: a fixed scroll, which is fixed in position and has a spiral-shaped wall body on one side face of an end plate; a swiveling scroll, which has a spiral-shaped wall body on one side face of an end plate, being supported by engaging of the wall bodies so as to move revolution swiveling as it is prevented rotating; top edges of the wall bodies being divided at a plurality of points, the height at each point becoming low on the center side of the spiral direction and becoming high on the outer side, thereby forming a step; and one side face of the end plates similarly being divided at a plurality of points, the height at each point becoming high on the center side of the spiral direction and becoming low on the outer side, thereby forming a step in correspondence with each of the points; the scroll compressor comprising a sealing member being provided on a join edge which joins adjacent points on the top edges and sliding against a join wall face which joins adjacent points on the side faces of the end plates; and a sealing member holding unit which prevents the sealing member from falling off a scroll member.
In the above scroll compressor, airtightness with the join wall face is increased without a need for high-precision processing by providing the sealing member on the join edge. Therefore, the compression ratio and capability of the scroll compressor is increased. The join edge and the join wall face are not constantly sliding against each other, but slide against each other only during a half-rotation of the swiveling scroll; there is no sliding at any other time. Furthermore, the scroll compressor comprises a sealing member holding unit which stops the sealing member from falling off even when the sealing member (tip seal) is not sliding; the sealing member holding unit is obtained by, for example, burying the sealing member (tip seal) of the step deeper than the lower tip seal face, thereby increasing the reliability of smooth operation.
A second aspect of the present invention is to provide, in the scroll compressor according to the first aspect, the sealing member holding unit comprising
a groove provided in the join edge; a filling section provided in the sealing member to be fitted into the groove; a narrower section provided at the opening of the groove and having a narrower width than the bottom section of the groove; and an enlarged section provided on the filling section and clipping into the narrower section so as to prevent the filling section from becoming removed from the groove.
In the above scroll compressor, the sealing member joined to the filling section is prevented from becoming separated from the groove even when the join edge and the join wall face are not sliding against each other, thereby increasing the reliability of smooth operation.
A third aspect of the present invention is to provide, in the scroll compressor according to the first aspect, the sealing member holding unit is a groove provided in the join edge, wherein the sealing member to be engaged in the groove connecting to at least one other sealing member which is engaged into the groove provided along each of the top edges, and engaging another end of the sealing member therein
In the above scroll compressor, since the sealing member of the step section connects to the other sealing member, the other end of the sealing member is engaged even when the join edge and the join wall face are not sliding against each other, preventing a cantilever support of the sealing member. Therefore, the sealing member is prevented from falling out of the groove, increasing the reliability of smooth operation.
A fourth aspect of the present invention is to provide, in the scroll compressor according to the first aspect, the sealing member holding unit comprising a groove provided in the join edge; a concavity which connects to the groove; and a convexity provided on the sealing member which is engaged into the groove with movable space.
In the above scroll compressor, the convexity provided on the sealing member is freely moved within movable space in the concavity, so that the sealing member does not fall out from the groove, thereby increasing the reliability of smooth operation.
A fifth aspect of the present invention is to provide, in the scroll compressor according to the second, third, or fourth aspect, an elastic material for applying a pressing force in the direction of the separation of the sealing member, provided in the groove, from the join edge, is provided to the groove.
In the above scroll compressor, the elastic material is provided to the groove, pressing the sealing member against the join wall face when the join edge and the join wall face are sliding against each other. Since better airtightness is achieved, the capability of the compressor is further increased.
A sixth aspect of the present invention is to provide, in the scroll compressor according to the first aspect, the sealing member holding unit comprising an elastic material, which is provided between the sealing member and the scroll member and connects the two members together.
In the above scroll compressor, the elastic material is provided to the groove, pressing the sealing member against the join wall face when the join edge and the join wall face are sliding against each other. Since better airtightness of the step section is achieved, the capability of the compressor is further increased. Moreover, when the join edge and the join wall face are not sliding against each other, the elastic material secures the sealing member and the join edge, preventing the sealing member from falling out from the groove. The groove depth (g) is made longer than the natural length (l0) of the elastic material (g greater than l0).
A seventh aspect of the present invention is to provide, in the scroll compressor according to the first, second, third, or fourth aspect, the dimensions of the sealing member at the time of its formation being set so that the tip of the sealing member touches the side wall of another scroll member when assembled with the other scroll member.
In the above scroll compressor, when the join edge and join wall face slide against each other, the sealing member holding unit in the scroll compressor according to the first, second, third, or fourth aspect is used, increasing the reliability of the compressor. Furthermore, since the dimensions of the sealing member at the time of its formation are set so that the tip of the sealing member touches the wall face (slide face) of the other scroll member when assembled, thereby increasing airtightness of the step during sliding.
An eighth aspect of the present invention is to provide, in the scroll compressor of any one of 1, 2, 3, 4, and 6th aspects, the sealing member comprising a polymer material.
In the above scroll compressor, since the sealing member comprises a polymer material, complex shapes can be manufactured with comparative ease.
A ninth aspect of the present invention is to provide, a scroll compressor comprising a fixed scroll, which is fixed in position and has a spiral-shaped wall body on one side face of an end plate; a swiveling scroll, which has a spiral-shaped wall body on one side face of an end plate, being supported by engaging of the wall bodies so as to move revolution swiveling as it is prevented rotating; top edges of the wall bodies being divided at a plurality of points, the height at each point being low on the center side of the spiral direction and being high on the outer side, thereby forming a step; one side face of the end plates similarly being divided at a plurality of points, the height at each point becoming high on the center side of the spiral direction and becoming low on the outer side, thereby forming a step in correspondence with each of the points; and a covering material, provided on a join wall face which joins adjacent points on a side face of each of the end plates, the covering material being worn away by the sliding of a join edge, which joins the adjacent points on the top edges.
In the above scroll compressor, the covering material starts wearing away from when the compressor starts operating, but some of the covering material remains in the gap between the join wall face and the join edge, enabling the join wall face to become accustomed to the join edge which rotates. Consequently, airtightness between the join edge and the join wall face is improved, further increasing the capability of the compressor.
A tenth aspect of the present invention is to provide a scroll compressor comprising a fixed scroll, which is fixed in position and has a spiral-shaped wall body on one side face of an end plate; a swiveling scroll, which has a spiral-shaped wall body on one side face of an end plate, being supported by engaging of the wall bodies so as to move revolution swiveling as it is prevented rotating; top edges of the wall bodies being divided at a plurality of points, the height at each point being low on the center side of the spiral direction and being high on the outer side, thereby forming a step; and one side face of the end plates similarly being divided at a plurality of points, the height at each point becoming high on the center side of the spiral direction and becoming low on the outer side, thereby forming a step in correspondence with each of the points; a join wall face, which joins adjacent points on a side face of each of the end plates, is separated from the end plate main body with a part of the end plate and can move in the spiral direction between adjacent wall bodies, the separated part of the end plate being pressed in the spiral direction by a pressing unit, provided between the separated part and the end plate main body.
In the above scroll compressor, one part of the separated end plate is pressed to the outside of the spiral direction by the pressing unit, pushing the join wall face against the join edge and thereby increasing airtightness. When the movable range of the part of the end plate is appropriately set, it is possible to push the join wall face against the join edge even while the join edge is not sliding against the join wall face. As a result, there is a high level of airtightness between the join edge and the join wall face, and they regularly slide against each other. Therefore, the capability of the scroll compressor is further increased.
An eleventh aspect of the present invention is to provide, in the scroll compressor of the tenth aspect, one of the end plate main body and the part of the end plate comprises a guide groove, provided along the spiral direction of the separated part of the end plate, and another of the end plate main body and the part of the end plate comprises a secured axial body, which is engaged into the guide groove and is allowed to move in the spiral direction within the guide groove.
In the above scroll compressor, the relationship between the guide groove and the axial body which is engaged therein with movable space specifies the movable range of the part of the separated end plate, enabling the part of the end plate to be led in that direction without obstruction, thereby ensuring that the compressor smoothly operates.
A twelfth aspect of the present invention is to provide a scroll compressor comprising a fixed scroll, which is fixed in position and has a spiral-shaped wall body on one side face of an end plate; a swiveling scroll, which has a spiral-shaped wall body on one side face of an end plate, being supported by engaging of the wall bodies so as to move revolution swiveling as it is prevented rotating; top edges of the wall bodies being divided at a plurality of points, the height at each point being low on the center side of the spiral direction and being high on the outer side, thereby forming a step; and one side face of the end plates similarly being divided at a plurality of points, the height at each point becoming high on the center side of the spiral direction and becoming low on the outer side, thereby forming a step in correspondence with each of the points; one or both of the fixed scroll and the swiveling scroll having a sealing member, provided along the points on the outer end side of the top edges of the wall bodies; and an inlet path which leads internal pressure of a compression chamber, formed by the points in the center side of side faces of the end plates, and a space which connects to the compression chamber, between the sealing member and the point on the outer end side of the top edges of the wall bodies.
In the above scroll compressor, the internal pressure of a compression chamber, formed by the points in the center side of side faces of the end plates, or a space (e.g. a discharge cavity or an oil chamber separated by an oil separator on the discharge side) which connects to the compression chamber, is led along an inlet path between the sealing member (a tip seal) and the point on the outer end side of the top edges of the wall bodies. Therefore, the internal pressure is much greater than in the compression chamber on the outer end side. The pressure increases the pushing force of the sealing member, enabling the sealing member to function adequately. Incidentally, a refrigerant or refrigerating machine oil can be used as the fluid which is led in order to transmit the internal pressure. Consequently, since leakage of the fluid from the compression chamber is prevented, there is no need for recompression power to compensate for the leaked fluid, eliminating power loss of the driving power and increasing the operating efficiency.
A thirteenth aspect of the present invention is to provided a scroll compressor comprising a fixed scroll, which is fixed in position and has a spiral-shaped wall body on one side face of an end plate; a swiveling scroll, which has a spiral-shaped wall body on one side face of an end plate, being supported by engaging of the wall bodies so as to move revolution swiveling as it is prevented rotating; top edges of the wall bodies being divided at a plurality of points, the height at each point being low on the center side of the spiral direction and being high on the outer side, thereby forming a step; and one side face of the end plates similarly being divided at a plurality of points, the height at each point becoming high on the center side of the spiral direction and becoming low on the outer side, thereby forming a step in correspondence with each of the points; wherein a groove is provided along the spiral direction on the top edges of each wall body; a sealing member, which slides to the plural points, is engaged in the groove; the groove connects a join edge joining the adjacent points on the top edges and further connects a concavity formed in the spiral direction from the join edge; and an end portion of the sealing member is engaged in the concavity.
In the above scroll compressor, since the end portion of the sealing member is embedded in the concavity on the scroll side, the sealing member is prevented from falling out of the groove even when the join edge and a join wall are separated each other, thereby increasing the reliability of smooth operation.